In the winter, set your thermostat at 68 degrees in daytime, and 55 degrees at night. Lowering your thermostat just two degrees during winter saves 6 percent of heating-related CO2 emissions. That’s a reduction of 420 pounds of CO2 per year for a typical home.

Clean or replace air filters as recommended. Energy is lost when air conditioners and hot-air furnaces have to work harder to draw air through dirty filters. Cleaning a dirty air conditioner filter can save 5 percent of the energy used. That could save 175 pounds of CO2 per year.

Try turning down the thermostat 5 to 10 degrees at night, and then turn it up again in the morning when the coffee is brewing. If you can get used to that, you’ll save 5 to 10 percent of your heating bill.

If you heat with electricity, you can take advantage of the individual room thermostats that make it possible to shut off unused rooms and to have cool settings in some rooms and warmer settings in others.